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<h1 align="center">SQL As Understood By SQLite</h1><p><a href="lang.html">[Top]</a></p><h2>Core Functions</h2>

<p>The core functions shown below are available by default. 
<a href="lang_datefunc.html">Date &amp; Time functions</a> and
<a href="lang_aggfunc.html">aggregate functions</a> are documented separately.  An
application may define additional
functions written in C and added to the database engine using
the <a href="c3ref/create_function.html">sqlite3_create_function()</a> API.</p>

<table border=0 cellpadding=10>
<tr><td valign="top" align="right" width="120"><a name="abs"></a>
abs(<i>X</i>)</td><td valign="top">
  The abs(X) function returns the absolute value of the numeric
  argument X.  Abs(X) returns NULL if X is NULL. 
  Abs(X) return 0.0 if X is a string or blob
  that cannot be converted to a numeric value.  If X is the 
  integer -9223372036854775807 then abs(X) throws an integer overflow
  error since there is no equivalent positive 64-bit two complement value.
</td></tr><tr><td valign="top" align="right" width="120"><a name="changes"></a>
changes()</td><td valign="top">
  The changes() function returns the number of database rows that were changed
  or inserted or deleted by the most recently completed INSERT, DELETE,
  or UPDATE statement, exclusive of statements in lower-level triggers.
  The changes() SQL function is a wrapper around the <a href="c3ref/changes.html">sqlite3_changes()</a>
  C/C++ function and hence follows the same rules for counting changes.
</td></tr><tr><td valign="top" align="right" width="120"><a name="coalesce"></a>
coalesce(<i>X</i>,<i>Y</i>,...)</td><td valign="top">
  The coalesce() function returns a copy of its first non-NULL argument, or
  NULL if all arguments are NULL.  Coalesce() must be at least 
  2 arguments.
</td></tr><tr><td valign="top" align="right" width="120"><a name="glob"></a>
glob(<i>X</i>,<i>Y</i>)</td><td valign="top">
  The glob(X,Y) function is equivalent to the
  expression "<b>Y GLOB X</b>".
  Note that the X and Y arguments are reversed in the glob() function
  relative to the infix <a href="lang_expr.html#glob">GLOB</a> operator.
  If the <a href="c3ref/create_function.html">sqlite3_create_function()</a> interface is used to
  override the glob(X,Y) function with an alternative implementation then
  the <a href="lang_expr.html#glob">GLOB</a> operator will invoke the alternative implementation.
</td></tr><tr><td valign="top" align="right" width="120"><a name="ifnull"></a>
ifnull(<i>X</i>,<i>Y</i>)</td><td valign="top">
  The ifnull() function returns a copy of its first non-NULL argument, or
  NULL if both arguments are NULL.  Ifnull() must have exactly 2 arguments.
  The ifnull() function is equivalent to <a href="lang_corefunc.html#coalesce">coalesce()</a> with two arguments.
</td></tr><tr><td valign="top" align="right" width="120"><a name="hex"></a>
hex(<i>X</i>)</td><td valign="top">
  The hex() function interprets its argument as a BLOB and returns
  a string which is the upper-case hexadecimal rendering of the content of
  that blob.
</td></tr><tr><td valign="top" align="right" width="120"><a name="last_insert_rowid"></a>
last_insert_rowid()</td><td valign="top">
  The last_insert_rowid() function returns the <a href="lang_createtable.html#rowid">ROWID</a>
  of the last row insert from the database connection which invoked the
  function.
  The last_insert_rowid() SQL function is a wrapper around the
  <a href="c3ref/last_insert_rowid.html">sqlite3_last_insert_rowid()</a> C/C++ interface function.
</td></tr><tr><td valign="top" align="right" width="120"><a name="length"></a>
length(<i>X</i>)</td><td valign="top">
  The length(X) function returns the length of X in 
  characters if X is a string, or in bytes if X is a blob.
  If X is NULL then length(X) is NULL.
  If X is numeric then length(X) returns the length of a string
  representation of X.
</td></tr><tr><td valign="top" align="right" width="120"><a name="like"></a>
like(<i>X</i>,<i>Y</i>)<br></br>like(<i>X</i>,<i>Y</i>,<i>Z</i>)</td><td valign="top">
  The like() function is used to implement the
  "<b>Y LIKE X &#91;ESCAPE Z&#93;</b>" expression. 
  If the optional ESCAPE clause is present, then the
  like() function is invoked with three arguments.  Otherwise, it is
  invoked with two arguments only. Note that the X and Y parameters are
  reversed in the like() function relative to the infix <a href="lang_expr.html#like">LIKE</a> operator.
  The <a href="c3ref/create_function.html">sqlite3_create_function()</a> interface can be used to override the
  like() function and thereby change the operation of the
  <a href="lang_expr.html#like">LIKE</a> operator.  When overriding the like() function, it may be important
  to override both the two and three argument versions of the like() 
  function. Otherwise, different code may be called to implement the
  <a href="lang_expr.html#like">LIKE</a> operator depending on whether or not an ESCAPE clause was 
  specified.
</td></tr><tr><td valign="top" align="right" width="120"><a name="load_extension"></a>
load_extension(<i>X</i>)<br></br>load_extension(<i>X</i>,<i>Y</i>)</td><td valign="top">
  The load_extension(X,Y) function loads SQLite extensions out of the shared
  library file named X using the entry point Y.  The result of load_extension()
  is always a NULL.  If Y is omitted then the default entry point
  of <b>sqlite3_extension_init</b> is used.  The load_extension() function
  raises an exception if the extension fails to load or initialize correctly.

  <p>The load_extension() function will fail if the extension attempts to 
  modify or delete a SQL function or collating sequence.  The
  extension can add new functions or collating sequences, but cannot
  modify or delete existing functions or collating sequences because
  those functions and/or collating sequences might be used elsewhere
  in the currently running SQL statement.  To load an extension that
  changes or deletes functions or collating sequences, use the
  <a href="c3ref/load_extension.html">sqlite3_load_extension()</a> C-language API.</p>
</td></tr><tr><td valign="top" align="right" width="120"><a name="lower"></a>
lower(<i>X</i>)</td><td valign="top">
  The lower(X) function returns a copy of string X with all ASCII characters
  converted to lower case.  The default built-in lower() function works
  for ASCII characters only.  To do case conversions on non-ASCII
  characters, load the ICU extension.
</td></tr><tr><td valign="top" align="right" width="120"><a name="ltrim"></a>
ltrim(<i>X</i>)<br></br>ltrim(<i>X</i>,<i>Y</i>)</td><td valign="top">
  The ltrim(X,Y) function returns a string formed by removing any and all
  characters that appear in Y from the left side of X.
  If the Y argument is omitted, ltrim(X) removes spaces from the left side
  of X.
</td></tr><tr><td valign="top" align="right" width="120"><a name="maxoreunc"></a>
max(<i>X</i>,<i>Y</i>,...)</td><td valign="top">
  The multi-argument max() function returns the argument with the 
  maximum value, or return NULL if any argument is NULL. 
  The multi-argument max() function searches its arguments from left to right
  for an argument that defines a collating function and uses that collating
  function for all string comparisons.  If none of the arguments to max()
  define a collating function, then the BINARY collating function is used.
  Note that <b>max()</b> is a simple function when
  it has 2 or more arguments but operates as an
  <a href="lang_aggfunc.html#minggunc">aggregate function</a> if given only a single argument.
</td></tr><tr><td valign="top" align="right" width="120"><a name="minoreunc"></a>
min(<i>X</i>,<i>Y</i>,...)</td><td valign="top">
  The multi-argument min() function returns the argument with the
  minimum value.
  The multi-argument min() function searches its arguments from left to right
  for an argument that defines a collating function and uses that collating
  function for all string comparisons.  If none of the arguments to min()
  define a collating function, then the BINARY collating function is used.
  Note that <b>min()</b> is a simple function when
  it has 2 or more arguments but operates as an 
  <a href="lang_aggfunc.html#maxggunc">aggregate function</a> if given
  only a single argument.
</td></tr><tr><td valign="top" align="right" width="120"><a name="nullif"></a>
nullif(<i>X</i>,<i>Y</i>)</td><td valign="top">
  The nullif(X,Y) function returns its first argument if the arguments are
  different and NULL if the arguments are the same.  The nullif(X,Y) function
  searches its arguments from left to right for an argument that defines a
  collating function and uses that collating function for all string
  comparisons.  If neither argument to nullif() defines a collating function
  then the BINARY is used.
</td></tr><tr><td valign="top" align="right" width="120"><a name="quote"></a>
quote(<i>X</i>)</td><td valign="top">
  The quote(X) function returns a string which is the value of
  its argument suitable for inclusion into another SQL statement.
  Strings are surrounded by single-quotes with escapes on interior quotes
  as needed.  BLOBs are encoded as hexadecimal literals.
</td></tr><tr><td valign="top" align="right" width="120"><a name="random"></a>
random()</td><td valign="top">
  The random() function returns a pseudo-random integer
  between -9223372036854775808 and +9223372036854775807.
</td></tr><tr><td valign="top" align="right" width="120"><a name="randomblob"></a>
randomblob(<i>N</i>)</td><td valign="top">
  The randomblob(N) function return an N-byte blob containing pseudo-random
  bytes. If N is less than 1 then a 1-byte random blob is returned.

  <p>Hint:  applications can generate globally unique identifiers
  using this function together with <a href="lang_corefunc.html#hex">hex()</a> and/or
  <a href="lang_corefunc.html#lower">lower()</a> like this:</p>

  <blockquote>
  hex(randomblob(16))<br></br>
  lower(hex(randomblob(16)))
  </blockquote>
</td></tr><tr><td valign="top" align="right" width="120"><a name="replace"></a>
replace(<i>X</i>,<i>Y</i>,<i>Z</i>)</td><td valign="top">
  The replace(X,Y,Z) function returns a string formed by substituting
  string Z for every occurrence of string Y in string X.  The <a href="datatype3.html#collation">BINARY</a>
  collating sequence is used for comparisons.  If Y is an empty
  string then return X unchanged.  If Z is not initially
  a string, it is cast to a UTF-8 string prior to processing.
</td></tr><tr><td valign="top" align="right" width="120"><a name="round"></a>
round(<i>X</i>)<br></br>round(<i>X</i>,<i>Y</i>)</td><td valign="top">
  The round(X,Y) function returns a string representation of the floating-point
  value X rounded to Y digits to the right of the decimal point.
  If the Y argument is omitted, the X value is truncated to an integer.
</td></tr><tr><td valign="top" align="right" width="120"><a name="rtrim"></a>
rtrim(<i>X</i>)<br></br>rtrim(<i>X</i>,<i>Y</i>)</td><td valign="top">
  The rtrim(X,Y) function returns a string formed by removing any and all
  characters that appear in Y from the right side of X.
  If the Y argument is omitted, rtrim(X) removes spaces from the right
  side of X.
</td></tr><tr><td valign="top" align="right" width="120"><a name="soundex"></a>
soundex(<i>X</i>)</td><td valign="top">
  The soundex(X) function returns a string that is the soundex encoding 
  of the string X.
  The string "?000" is returned if the argument is NULL or contains
  no ASCII alphabetic characters.
  This function is omitted from SQLite by default.
  It is only available if the <a href="compile.html#soundex">SQLITE_SOUNDEX</a> compile-time option
  is used when SQLite is built.
</td></tr><tr><td valign="top" align="right" width="120"><a name="sqlite_compileoption_get"></a>
sqlite_compileoption_get(<i>N</i>)</td><td valign="top">
  The sqlite_compileoption_get() SQL function is a wrapper around the
  <a href="c3ref/compileoption_get.html">sqlite3_compileoption_get()</a> C/C++ function.
  This routine returns the N-th compile-time option used to build SQLite
  or NULL if N is out of range.  See also the <a href="pragma.html#pragma_compile_options">compile_options pragma</a>.
</td></tr><tr><td valign="top" align="right" width="120"><a name="sqlite_compileoption_used"></a>
sqlite_compileoption_used(<i>X</i>)</td><td valign="top">
  The sqlite_compileoption_used() SQL function is a wrapper around the
  <a href="c3ref/compileoption_get.html">sqlite3_compileoption_used()</a> C/C++ function.
  When the argument X to sqlite_compileoption_used(X) is a string which
  is the name of a compile-time option, this routine returns true (1) or
  false (0) depending on whether or not that option was used during the
  build.
</td></tr><tr><td valign="top" align="right" width="120"><a name="sqlite_source_id"></a>
sqlite_source_id()</td><td valign="top">
  The sqlite_source_id() function returns a string that identifies the
  specific version of the source code that was used to build the SQLite
  library.  The string returned by sqlite_source_id() begins with
  the date and time that the source code was checked in and is follows by
  an SHA1 hash that uniquely identifies the source tree.  This function is
  an SQL wrapper around the <a href="c3ref/libversion.html">sqlite3_sourceid()</a> C interface.
</td></tr><tr><td valign="top" align="right" width="120"><a name="sqlite_version"></a>
sqlite_version()</td><td valign="top">
  The sqlite_version() function returns the version string for the SQLite
  library that is running.  This function is an SQL
  wrapper around the <a href="c3ref/libversion.html">sqlite3_libversion()</a> C-interface.
</td></tr><tr><td valign="top" align="right" width="120"><a name="substr"></a>
substr(<i>X</i>,<i>Y</i>,<i>Z</i>)<br></br>substr(<i>X</i>,<i>Y</i>)</td><td valign="top">
  The substr(X,Y,Z) function returns a substring of input string X that begins
  with the Y-th character and which is Z characters long.
  If Z is omitted then substr(X,Y) returns all characters through the end
  of the string X beginning with the Y-th.
  The left-most character of X is number 1.  If Y is negative
  then the first character of the substring is found by counting from the
  right rather than the left.  If Z is negative then
  the abs(Z) characters preceding the Y-th character are returned.
  If X is a string then characters indices refer to actual UTF-8 
  characters.  If X is a BLOB then the indices refer to bytes.
</td></tr><tr><td valign="top" align="right" width="120"><a name="total_changes"></a>
total_changes()</td><td valign="top">
  The total_changes() function returns the number of row changes
  caused by INSERT, UPDATE or DELETE
  statements since the current database connection was opened.
  This function is a wrapper around the <a href="c3ref/total_changes.html">sqlite3_total_changes()</a>
  C/C++ interface.
</td></tr><tr><td valign="top" align="right" width="120"><a name="trim"></a>
trim(<i>X</i>)<br></br>trim(<i>X</i>,<i>Y</i>)</td><td valign="top">
  The trim(X,Y) function returns a string formed by removing any and all
  characters that appear in Y from both ends of X.
  If the Y argument is omitted, trim(X) removes spaces from both ends of X.
</td></tr><tr><td valign="top" align="right" width="120"><a name="typeof"></a>
typeof(<i>X</i>)</td><td valign="top">
  The typeof(X) function returns a string that indicates the <a href="datatype3.html">datatype</a> of
  the expression X: "null", "integer", "real", "text", or "blob".
</td></tr><tr><td valign="top" align="right" width="120"><a name="upper"></a>
upper(<i>X</i>)</td><td valign="top">
  The upper(X) function returns a copy of input string X in which all 
  lower-case ASCII characters are converted to their upper-case equivalent.
</td></tr><tr><td valign="top" align="right" width="120"><a name="zeroblob"></a>
zeroblob(<i>N</i>)</td><td valign="top">
  The zeroblob(N) function returns a BLOB consisting of N bytes of 0x00.
  SQLite manages these zeroblobs very efficiently.  Zeroblobs can be used to
  reserve space for a BLOB that is later written using 
  <a href="c3ref/blob_open.html">incremental BLOB I/O</a>.
  This SQL function is implemented using the <a href="c3ref/result_blob.html">sqlite3_result_zeroblob()</a>
  routine from the C/C++ interface.
</td></tr>
</table>


